Patent Number: 8,797,542

Title: Measurement apparatus

Abstract: A measurement apparatus which measures a distance between a reference surface and a test surface, comprises a light source unit including a plurality of light sources each corresponding to one of a plurality of wavelength scanning ranges and each continuously scans a wavelength of generated light in the corresponding wavelength scanning range, an interferometer unit which splits light emitted by each of the plurality of light sources into reference light and test light, and detects, as an interference signal, an interference fringe formed by the reference light and the test light, and a processor which determines a slope of a phase of the interference signal with respect to wave number of the light based on the interference signal detected by the interferometer unit for each of the plurality of wavelength scanning ranges, and determines the distance from the slope of the phase.

Inventors: Tokimitsu; Takumi (Moka, JP), Kuramoto; Yoshiyuki (Utsunomiya, JP)

Assignee: Canon Kabushiki Kaisha

International Classification: G01B 9/02 (20060101)

Expiration Date: 8/05/12018